This invention relates generally to lever operated type hoisting devices and more particularly to a device for lever hoists which permits in one selected mode the free-chain release of the hoisting chain to allow rapid deployment of the chain without the need for hand cranking out the chain.
Lever operated type hoists are known in the prior art. One of the prior art devices includes a spring interposed between a driving member which is repeatedly driven by lever and a driven member of a braking assembly for releasing the brake. With this known device the spring force always acts in a direction releasing the brake assembly. Since the spring force always acts in a direction releasing the braking assembly, light loads which are insufficient to load the brake assembly against the spring force cannot be lifted. In addition, when lowering a light load it is possible to obtain an unwanted brake release causing the load to drop with the result that such a light load cannot be lowered in a controlled fashion by the rocking movement of the lever.
Several solutions have been proposed to overcome this problem, however, to date the solutions have required the use of complicated mechanisms involving the use of opposed torsion springs requiring more complex mechanisms to effect the deployment of the chain idling or free-chain device.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.